You may have already seen it pass by, plants with their roots in a vase of water. And perhaps you have already put plants in water yourself, for example when you were going to take cuttings. Growing a plant on water is called hydroponics. This variety has stiff, leathery leaves that are a dark olive green in color. It gets the name 'Autograph tree' because the leaves are said to be so tough, you could carve your name into them.